JP6631106B2 - Gear pump or gear motor - Google Patents

Description

  The present invention relates to, for example, a gear pump or a gear motor including two gears that mesh with each other.

  2. Description of the Related Art As a conventional gear pump, there is a gear pump including two gears meshing with each other and a casing for housing the two gears, and the tip of a tooth tip of the gear rotates close to the inner peripheral surface of the casing. When the gap between the tip of the tooth tip and the inner peripheral surface of the casing is large, the hydraulic oil leaks from the gap and the efficiency is deteriorated, but in order to reduce the gap, it is necessary to reduce the outer diameter of the gear and the inner peripheral surface of the casing. Need to improve accuracy. However, conventionally, it is difficult to increase the precision in machining, so it is necessary to perform operation (break-in operation) at a pressure slightly higher than the operating pressure before shipping and cut the inner peripheral surface of the casing at the tip of the tooth tip. The gap. In Patent Literature 1, in order to improve the machinability of the tip of the tip of the gear, the end face on the rotation direction side of the cutting portion of the tip of the tip is formed at an angle of at least a right angle to the inner peripheral surface of the casing. The cutting function of the cutting section during break-in operation has been improved, and break-in operation has been shortened.

JP-A-11-210644

  However, in a gear pump or a gear motor that seals by meshing between the tooth tip and the tooth bottom, when the tip of the tooth tip meshes with the tooth bottom of the other gear during driving, the cutting part of the tooth tip is the other. Since the tooth bottom of the gear is cut, the sealing performance between the tip of the tooth tip and the tooth bottom of the other gear is deteriorated.

  Therefore, an object of the present invention is to provide a gear pump or a gear motor that can prevent deterioration of the sealing performance between the tip of the tooth tip and the bottom of the other gear.

A gear pump or gear motor according to the first invention comprises a first gear and the second gear mesh with each other, and a casing for housing the first gear and second gear, the tooth tip of the first tooth car A base portion and a step portion projecting from the base portion toward the inner peripheral surface of the casing and having a rising surface on the rotation direction side of the first gear are formed, and the rising surface has a tip end of the step portion. when in contact with the inner peripheral surface of the casing, with increasing distance from the tip is configured so that the distance of the rotating direction from the normal line increases at the contact point between the tip and the inner peripheral surface of the casing An angle formed between the rising surface and a portion of the inner peripheral surface of the casing that faces the rising surface is an acute angle, and the rising surface and a surface of the base that connects to the rising surface. Nasu angle, characterized in that it is an obtuse angle.

  In this gear pump or gear motor, during the break-in operation, the step between the tooth tips of the gear cuts the inner peripheral surface of the casing, so that the gap between the tooth tip of the gear and the inner peripheral surface of the casing is reduced. Sealability can be improved. Further, as the rising surface of the step portion is away from the tip, the distance in the rotation direction from the normal line at the point of contact with the casing is configured to be large, thereby suppressing the cutability of the step portion. Therefore, it is possible to prevent the stepped portion at the tooth tip of the first gear from shaving the bottom of the second gear during driving of the gear, and to maintain a high sealing property between the first gear and the second gear.

  A gear pump or a gear motor according to a second invention is characterized in that, in the first invention, the hardness of the first gear and the second gear is greater than the hardness of an inner peripheral surface of the casing.

  In this gear pump or gear motor, the step portion at the tip of the first gear prevents the tooth bottom of the second gear from shaving during driving of the gear, so that the high gear between the first gear and the second gear is prevented. The sealing property can be maintained.

Third gear pump or gear motor according to the present invention, in the first or second invention, the front Symbol stepped portion, on the opposite side of the rotation direction of the first gear, has another rising surface, said another The rising surface is configured such that, when the distal end contacts the inner peripheral surface of the casing, as the distance from the distal end increases, a distance in a direction opposite to the rotation direction from the normal increases. An angle formed between another rising surface and a surface of the base portion connected to the another rising surface is an obtuse angle .

  With this gear pump or gear motor, the inner peripheral surface of the casing can be appropriately cut at the tip of the tooth tip in the break-in operation regardless of the rotation direction of the pump or motor.

  A gear pump or a gear motor according to a fourth invention is provided in any one of the first to third inventions, wherein the gear pump or the gear motor is formed at a root of the second gear, and the tip of the first gear and the tooth of the second gear It has a receiving groove for accommodating the step when the bottom is engaged.

  In this gear pump or gear motor, the step portion is accommodated in the receiving groove during driving of the gear, so that the tooth tip and the tooth bottom smoothly mesh with each other. As a result, continuous meshing between the tooth tip and the tooth bottom can be realized, and the sealing property between the gears can be maintained.

A gear pump or a gear motor according to a fifth invention is characterized in that, in any one of the first to fourth inventions, the first gear and the second gear are helical gears.

  In this gear pump or gear motor, a helical gear that requires higher sealing performance because the gears mesh with each other more continuously than a spur gear has, during driving of the gear, the stepped portion of the tip of the gear has the other gear. Can be prevented from shaving the tooth bottom.

  As described above, according to the present invention, the following effects can be obtained.

  In the first invention, the step between the teeth of the gear cuts the inner peripheral surface of the casing during the break-in operation, so that the gap between the tooth of the gear and the inner peripheral surface of the casing is reduced to improve the sealing performance. Can be improved. Further, as the rising surface of the step portion is away from the tip, the distance in the rotation direction from the normal line at the point of contact with the casing is configured to be large, thereby suppressing the cutability of the step portion. Therefore, it is possible to prevent the stepped portion at the tooth tip of the first gear from shaving the bottom of the second gear during driving of the gear, and to maintain a high sealing property between the first gear and the second gear.

  In the second invention, a step portion at the tooth tip of the first gear is prevented from shaving the bottom of the second gear during driving of the gear, so that a high sealing property between the first gear and the second gear is provided. Can be maintained.

  In the third invention, the inner peripheral surface of the casing can be appropriately cut at the tip of the tooth tip in the break-in operation regardless of the rotation direction of the pump or the motor.

  According to the fourth aspect, the step portion is accommodated in the receiving groove during driving of the gear, so that the tooth tip and the tooth bottom smoothly mesh with each other. As a result, continuous meshing between the tooth tip and the tooth bottom can be realized, and the sealing property between the gears can be maintained.

  According to the fifth aspect of the present invention, a helical gear that requires a high sealing property because the gears mesh with each other more continuously than the spur gear, has a step portion at the tip of the tooth of the other gear during driving of the gear. Shaving the bottom can be prevented.

It is a figure explaining the whole gear pump composition concerning an embodiment of the present invention. It is a figure explaining composition of a drive gear and a driven gear. FIG. 3 is a sectional view taken along line III-III in FIG. 1. It is a figure showing composition of a tooth tip of a gear. It is a figure showing the composition of the tooth tip of the gear of the gear pump concerning a modification of the present invention. It is a figure showing composition of a gear root of a gear of a gear pump concerning a modification of the present invention.

  Hereinafter, embodiments of a gear pump according to the present invention will be described with reference to the drawings.

[Overall configuration of gear pump]
As shown in FIG. 1, the gear pump 1 of the embodiment includes a driving gear 2 and a driven gear 3 that mesh with each other, and driving shafts 4a and 4b and driven shafts 5a and 5b that support the driving gear 2 and the driven gear 3, respectively. , A drive gear 2, a driven gear 3, a drive shaft 4a, 4b, and a casing 6 for accommodating the driven shafts 5a, 5b. The gear pump 1 according to the present embodiment is for pumping, for example, a working fluid supplied from a tank for storing a working fluid (for example, a working oil) to increase the pressure, and then discharging the working fluid to supply the same to hydraulic equipment.

  The casing 6 has a main body 7 having an internal space (eyeglass holes 10) having a substantially figure-eight cross section, a mounting 8 screwed to one end surface of the main body 7, and a screwing to the other end surface of the main body 7. Cover 9. In the gear pump 1, the eyeglass hole 10 formed inside the main body 7 is closed by the mounting 8 and the cover 9.

  As shown in FIGS. 1 and 2, the drive gear 2 and the driven gear 3 are each configured as a helical gear, and are inserted into eyeglass holes 10 formed inside the casing 6. In the eyeglass hole 10, the drive shafts 4 a and 4 b extend in the axial direction from both end surfaces of the drive gear 2, and the driven shafts 5 a and 5 b extend in the axial direction from both end surfaces of the driven gear 3. You. The drive shaft 4a is inserted into an insertion hole 8a formed in the mounting 8, and a drive unit (not shown) is connected to an end of the drive shaft 4a. In the gear pump 1, the driving gear 2 and the driven gear 3 are housed in the eyeglass hole 10 in a state of being meshed with each other, and the tooth tip thereof is on the inner peripheral surface 6 a of the casing 6 (the inner peripheral surface of the eyeglass hole 10). It comes into sliding contact. The hardness of the driving gear 2 and the driven gear 3 is greater than the hardness of the inner peripheral surface 6 a of the casing 6.

  In FIG. 1, a spectacle hole 10 formed inside the casing 6 has a bearing case 11 that supports a drive shaft 4 a extending leftward from the drive gear 2, and a leftward direction from the driven gear 3. A bearing case 111 that supports the extended driven shaft 5a is inserted. Each of the bearing cases 11 and 111 has one support hole. In the support holes, a bearing 11a as a bearing for the drive shaft 4a and a bearing 111a as a bearing for the driven shaft 5a are provided. Therefore, the bearing case 11 rotatably supports the drive shaft 4a by inserting the drive shaft 4a into the bearing 11a, and the bearing case 111 includes the driven shaft 5a by inserting the driven shaft 5a into the bearing 111a. Is rotatably supported.

  Similarly, in a spectacle hole 10 formed inside the casing 6, a bearing case 12 supporting a drive shaft 4b extending rightward from the drive gear 2 and a rightward The bearing case 112 that supports the driven shaft 5b extending toward is inserted. Each of the bearing cases 12 and 112 has one support hole, and a bearing 12a as a bearing for the drive shaft 4b and a bearing 112a as a bearing for the driven shaft 5b are provided in the support holes. Therefore, the bearing case 12 rotatably supports the drive shaft 4b when the drive shaft 4b is inserted into the bearing 12a, and the bearing case 112 allows the driven shaft 5b to be inserted when the driven shaft 5b is inserted into the bearing 112a. Is rotatably supported.

  On both sides of the driving gear 2 and the driven gear 3, two side plates 15a and 15b are arranged, respectively. The side plate 15a is a plate-shaped member in which two through holes are formed. The side plate 15a contacts the end surfaces of the drive gear 2 and the driven gear 3 with the drive shaft 4a and the driven shaft 5a inserted through the two through holes. Touch Similarly, the side plate 15b is a plate-shaped member in which two through holes are formed, and the drive gear 4 and the driven gear 3 are inserted into the two through holes while the drive shaft 4b and the driven shaft 5b are inserted therethrough. Contact the end face. Therefore, the side plate 15a is disposed between the driving gear 2 and the driven gear 3 and the bearing cases 11 and 111, and the side plate 15b is disposed between the driving gear 2 and the driven gear 3 and the bearing cases 12 and 112. Placed in

  The end faces of the bearing cases 11, 111 facing the side plate 15a are provided with elastic sealing members 11b, respectively. The seal member 11b divides a gap between the bearing cases 11, 111 and the side plate 15a into a high-pressure side and a low-pressure side. The other end face of the bearing case 11 is in contact with the end face of the mounting 8, whereby the movement of the bearing cases 11 and 111 in the axial direction is restricted. Similarly, an elastic seal member 12b is provided on each of the end faces of the bearing cases 12, 112 facing the side plate 15b. The seal member 12b divides a gap between the bearing cases 12, 112 and the side plate 15b into a high-pressure side and a low-pressure side. The other end surfaces of the bearing cases 12, 112 are in contact with the end surfaces of the cover 9, whereby the movement of the bearing cases 12, 112 in the axial direction is restricted.

  In the gear pump 1, as shown in FIG. 3, a suction hole 7a communicating with the low-pressure space of the spectacle hole 10 is formed on one side of the main body 7, and a spectacle hole is formed on the other side opposite to the suction hole 7a. A discharge hole 7b communicating with the high-pressure space 10 is formed. The suction hole 7a and the discharge hole 7b are provided such that their respective axes are located at the centers between the rotation axes of the driving gear 2 and the driven gear 3.

  Therefore, in the gear pump 1, the pipe from the tank storing the working fluid is connected to the suction hole 7 a of the casing 6, and the pipe toward the hydraulic device is connected to the discharge hole 7 b. The shaft 4a is rotated by driving means (not shown). Thereby, the driven gear 3 meshed with the driving gear 2 rotates, and the operation of the space surrounded by the inner peripheral surface 6a of the casing 6 (the inner peripheral surface of the eyeglass hole 10) and the tooth surfaces of the driving gear 2 and the driven gear 3 is performed. The fluid is transferred to the discharge hole 7b side by the rotation of the gear, and the discharge hole 7b side becomes the high pressure side and the suction hole 7a side becomes the low pressure side with the meshing portion of the driving gear 2 and the driven gear 3 as a boundary.

  When the working fluid is transferred to the discharge hole 7b side and the suction hole 7a side becomes negative pressure, the working fluid in the tank is sucked into the eyeglass hole 10 on the low pressure side through the pipe and the suction hole 7a, and the casing 6 The working fluid in the space surrounded by the inner peripheral surface 6a (the inner peripheral surface of the eyeglass hole 10) and the tooth surfaces of the drive gear 2 and the driven gear 3 is transferred to the discharge hole 7a side by the rotation of the gear, and is subjected to high pressure. It is pressurized and sent to the hydraulic equipment via the discharge hole 7a and the pipe.

  The drive gear 2 and the driven gear 3 have step portions 2a, 3a formed near the tips of the tooth tips, respectively. The steps 2a, 3a are formed over the entire lengths of the driving gear 2 and the driven gear 3, respectively, and are configured to be able to face the inner peripheral surface 6a of the casing 6. The width (circumferential length) of the steps 2a, 3a is in the range of 0.1 mm-1 mm, and the height is 0.1 mm or less. 2 and 3, the steps 2a, 3a are not shown, and in FIG. 4, the steps 2a, 3a are exaggerated.

  FIG. 4 shows a cross section perpendicular to the axial direction of the drive gear 2. A step 2 a formed at the tooth tip of the drive gear 2 faces the inner peripheral surface 6 a of the casing 6. As shown in FIG. 4, when the tip of the stepped portion 2a contacts the inner peripheral surface 6a of the casing 6, the distance from the normal to the contact point A in the rotational direction becomes larger as the distance from the tip increases. have. In the present embodiment, the step portion 2a is formed on all the tooth tips of the drive gear 2 and is formed in a projecting shape that becomes thinner toward the tip.

  Similarly, a step 3a is formed at the tooth tip of the driven gear 3, but the description is omitted because it has the same configuration as the step 2a of the driving gear 2.

<Features of the gear pump of the present embodiment>
The gear pump 1 of the present embodiment has the following features.

  In the gear pump 1 of the present embodiment, the stepped portion of the tooth tips of the drive gear 2 and the driven gear 3 cuts the inner peripheral surface 6a of the casing 6 during the break-in operation. The gap between the inner peripheral surface 6a of the casing 6 and the inner peripheral surface 6a can be reduced to improve the sealing performance. Further, as the rising surfaces 2b, 3b of the steps 2a, 3a move away from the front end, the distance in the rotational direction from the normal line at the point of contact A with the casing 6 is configured to be large, thereby suppressing the machinability of the steps. Therefore, it is possible to prevent the stepped portion of the tooth tip from shaving the bottom of the other gear during driving of the gear, and to maintain a high sealing property between the driving gear 2 and the driven gear 3.

  In the gear pump 1 of the present embodiment, since the step portions 2a, 3a are formed in the shape of a projection that becomes thinner toward the tip, the running-in operation does not depend on the rotation direction of the pump or the motor. The inner peripheral surface of the casing can be appropriately cut.

  As described above, the embodiments of the present invention have been described with reference to the drawings. However, it should be considered that the specific configuration is not limited to these embodiments. The scope of the present invention is defined by the terms of the claims, rather than the description of the embodiments described above, and further includes all modifications within the scope and meaning equivalent to the terms of the claims.

  In the above-described embodiment, the case where the step portions 2a and 3a of the driving gear 2 and the driven gear 3 are formed in the shape of a projection that becomes thinner toward the tip end is described. However, as shown in FIG. When the distal end of the surface 3a contacts the inner peripheral surface 6a of the casing 6 when the distal end thereof comes into contact with the inner peripheral surface 6a, the rising surfaces 2b and 3b whose distance in the rotational direction from the normal line at the contact point A increases as the distal end moves away from the distal end. If it does, the shape of the step may be changed. Further, the step portion may be formed on at least one tooth tip of the driving gear 2 and the driven gear 3.

  In the above-described embodiment, the case where the driving gear 2 and the driven gear 3 have the step portions 2a and 3a formed at the tooth tips, and the receiving groove for accommodating the step portions 2a and 3a is not formed at the tooth bottom has been described. However, at least one of the driving gear 2 and the driven gear 3 may be formed at the bottom of the tooth thereof, and may have a receiving groove for accommodating the steps 2a, 3a when meshing with the other gear. FIG. 6 shows a state in which the tooth tip of the driven gear 3 and the tooth bottom of the drive gear 2 are engaged with each other, and the tooth bottom of the drive gear 2 has a receiving groove 2c for accommodating the step 3a of the tooth tip of the driven gear 3. Are formed on all tooth bottoms. FIG. 6 illustrates a case where the receiving groove 2c has substantially the same shape as the step portion 3a and substantially the entire step portion 3a is accommodated in the receiving groove 2c. However, the receiving groove 2c is formed larger than the step portion 3a. It may accommodate the step 3a. In this case, the stepped portion 3a is housed in the receiving groove 2c during driving of the gear, so that the tooth tip and the tooth bottom smoothly mesh with each other. As a result, continuous meshing between the tooth tip and the tooth bottom can be realized, and the sealing property between the gears can be maintained. Although not shown, in a state where the tooth tip of the driving gear 2 and the tooth bottom of the driven gear 3 are engaged with each other, the receiving groove 3c for receiving the stepped portion 2a of the tooth tip of the driving gear 2 in the tooth bottom of the driven gear 3. The same effect can be obtained even when is formed.

  In the above-described embodiment, the case where the step portions 2a and 3a are formed on all the tooth tips of the drive gear 2 and the driven gear 3 has been described, but the step portions 2a and 3a are at least one of the drive gear 2 and the driven gear 3. It may be formed on one tooth tip.

In the above embodiment, the driving gear and the driven gear is described a case where the helical gear, the drive gear and the driven gear may be a spur wheel.

  In the above embodiment, the case where the present invention is applied to the gear pump has been described, but the present invention may be applied to a gear motor configured similarly to the gear pump.

  According to the present invention, it is possible to prevent the sealing performance between the tip of the tooth tip and the bottom of the other gear from deteriorating.

Reference Signs List 1 gear pump 2 drive gear 2a stepped portion 2b rising surface 2c receiving groove 3 driven gear 3a stepped portion 3b rising surface 3c receiving groove 4 drive shaft 5 driven shaft 6 casing

Claims (5)

A first gear and a second gear that mesh with each other;
A casing that houses the first gear and the second gear,
Wherein the tooth tip of the first tooth wheel, base and has a step portion having a rising surface is formed on the rotational direction side of the base portion from projecting toward the inner peripheral surface of the casing and the first gear,
The rising surface, when the tip of the stepped portion is in contact with the inner peripheral surface of the casing, with increasing distance from the tip, the rotating direction of the normal line at the contact point between the tip and the inner peripheral surface of the casing Is configured to increase the distance of
An angle formed between the rising surface and a portion of the inner peripheral surface of the casing facing the rising surface is an acute angle,
The angle between the rising surface and a surface of the base portion connected to the rising surface is an obtuse angle .   The gear pump or the gear motor according to claim 1, wherein the hardness of the first gear and the second gear is greater than the hardness of an inner peripheral surface of the casing. The step portion has another rising surface on the opposite side of the rotation direction of the first gear,
The other rising surface is configured such that, when the tip comes into contact with the inner peripheral surface of the casing, as the distance from the tip increases, the distance from the normal in the direction opposite to the rotation direction increases. ,
The gear pump or the gear motor according to claim 1 , wherein an angle formed between the another rising surface and a surface of the base portion connected to the another rising surface is an obtuse angle .   2. A receiving groove formed in the bottom of the second gear and accommodating the step when the tip of the first gear meshes with the bottom of the second gear. 3. The gear pump or the gear motor according to any one of items 1-3. The gear pump or the gear motor according to claim 1, wherein the first gear and the second gear are helical gears.

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